Russian prosecutors say a safety breach has caused a radiation leak at a nuclear reprocessing plant in the Ural mountains.

Local officials say a valve believed to be defective allowed radiation to leak from a tank that was holding radioactive liquid waste. The incident occurred on Thursday as the tank was being transported between units of the Mayak plant, near Yekaterinburg.

Prosecutors called the incident a flagrant breach of safety rules in waste transportation.

Officials decontaminated the area and said the radiation is normal inside the plant. No one was injured during the incident.

Russia's Interfax news agency reports Mayak's administration has created a commission to investigate the incident.